1. Field of Invention
The present invention relates to a display panel assembly suitable for devices using a liquid crystal panel for display control, a display panel case, a display panel module, a projection display device, and a cooling method for the display panel module.
2. Description of Related Art
A liquid crystal panel has a structure in which liquid crystal is sealed between two substrates, such as glass substrates or quartz substrates. In the liquid crystal panel, active elements, such as thin film transistors (hereinafter “TFTs”), are arranged in a matrix on one of the substrates, and a counter electrode is placed on the other substrate. Image display can be performed by changing the optical characteristic of the liquid crystal layer sealed between the substrates according to an image signal.
That is, an image signal is supplied to each of pixel electrodes arranged in a matrix by a TFT element, and a voltage based on the image signal is applied to the liquid crystal layer between the pixel electrode and the counter electrode, thereby changing the alignment of liquid crystal molecules. The transmittance of the pixel is thereby changed, and light passing through the pixel electrode and the liquid crystal layer is changed according to the image signal to perform image display.
Such a liquid crystal panel can be used as a light valve that receives light from a light source to form a predetermined image in a projection display device. An image formed by the liquid crystal panel is enlarged and projected on a screen or the like by a projection optical system of the projection display device.
In this way, in the projection display device, an image on an image plane of the liquid crystal panel is enlarged and projected on the screen. Therefore, when dust adheres to the image plane of the liquid crystal panel, the quality of a display image is significantly lowered by the influence of the dust. Accordingly, a dustproof panel is attached to at least an incident surface of the liquid crystal panel in order to reduce the influence of dust and the like by a defocusing effect.
In the projection display device, in general, a liquid crystal panel assembly in which a dustproof panel is attached to a liquid crystal panel is housed in a case made of synthetic resin, metal, or the like, and is mounted inside a housing of the device from the standpoints of strength, mounting accuracy, and so on.
The dustproof panel and the liquid crystal panel are fixed by adhesive. Furthermore, a gap between side faces of the liquid crystal panel and inner walls of the case is sealed with adhesive to fixedly bond the liquid crystal panel to the case.
An opening is formed at the bottom center of the case corresponding to an effective display region of the liquid crystal panel. Light incident from the opening is transmitted by the liquid crystal panel through the dustproof panel, and is then emitted. A flexible print board is fixed to mounting terminals provided at the substrate end of the liquid crystal panel by pressure.